Corona shield for ionizer wires



1967 E. c. HOISINGTON ETAL 3,354,617

CORONA SHIELD FOR IONIZER WIRES Filed Oct. 14, 1966 INVENTORS EDWARD c. HOISING'T'ON CLEMENT MHRTZOL FF L TNNE$ I 5252740 Jo /v M 945 United States Patent 3,354,617 CORONA SHIELD FQlR IGNIZER WIRES Edward C. Hoisizugton and Clement L. Martzolff, Detroit,

Mich, assignors to American Standard Inc, a corporation of Delaware Filed Oct. 14, 1966, Ser. No. 586,371 10 Claims. (Cl. 55-147) This invention relates to an electrostatic precipitator of the type used to remove dust or ash particles from gas exhausted out of large industrial furnaces, as in power plants, steel mills, etc. More particularly this invention concerns improved means for suspending the ionizer wires commonly used in this type precipitator.

One object of the invention is to provide a wiresuspending mechanism which will not break loose from the wire.

A further object is to provide a wire-suspending mechanism which includes a corona shield therein.

Another object is to provide a wire-suspending mechanism which will not form stress riser cracks in the wire when the wire is subject to vertical vibrations or pendulum movements.

An additional object is to provide a wire-suspending mechanism manufacturable at low cost and which is readily installable in the field.

In the drawings:

FIG. 1 is a sectional elevational view of a precipitator employing the invention.

FIG. 2 is an enlarged elevational view of a wire'suspending mechanism employed in the FIG. 1 precipitator.

FIG. 3 is a left-end view of the FIG. 2 mechanism.

FIG. 4 is an enlarged view of a weight assembly used in the FIG. 1 precipitator to maintain each ionizer wire in a taut condition.

FIG. 5 is a reduced view of an alternate to the FIG. 2 wire-suspending mechanism.

FIG. 6 is a reduced view of an alternate to the FIG. 4 weight assembly.

The general arrangement The FIG. 1 arrangement comprises an upright housing located to have gas pass therethrough in the arrow 11 direction. The gas travels between parallel collector plates 52 arranged in planes parallel to the plane of the paper. The number of collector plates may be varied, depending on the quantity of gas to be handled. In large units upwards of one hundred plates might be employed. Between the opposing faces of adjacent plates there are provided a number of negatively charged vertically disposed ionizer wires 42; FIG. 1 shows six wires adjacent each plate although more or less than that number could be employed. Each collector plate 52 may have a height of about thirty feet and a width of about four feet. The spacing between adjacent plates may be about nine inches, with the ionizer wires located midway between the plates. The plate-wire spacing would then be on the order of about four inches. Adjacent wires in each set of six wires may be spaced about seven inches apart. Each wire is commonly about .09 inch in diameter.

As the gas moves in the arrow 11 direction the gas and any entrained solid particles are negatively charged by the electric field surrounding each wire 42. The negatively charged particles are then deposited on the grounded or positively charged plates 52. Periodically the plates are vibrated in vertical and/ or horizontal directions to discharge the collected particles into a hopper 53. At very infrequent periods the ionizer wires 42 may be vibrated to shake loose any dust particles which may have inadvertently collected thereon.

In some cases the precipitator may include a number of collector stages arranged in series, following one an- 3,354,617 Patented Nov. 28, 1967 other. Thus, as shown in FIG. 1, housing 9 may continue rightwardly beyond the illustrated structure to contain one or more additional collector stages.

The structure in greater detail As shown in FIG. 1, the precipitator comprises a housing 9 having a top wall 10 and a front wall 12 provided with a dust laden gas inlet opening 14. Suitably supported on top wall 10 are two hollow porcelain cylinders 16; the two cylinders 16 are located one behind the other, and thus only one is Visible in FIG. 1. Each cylinder is associated with a pair of metal leveling plate assemblies 18 and 2t) containing half moon support sections 23. Leveling screws 21 are arranged between each set of leveling plates to cause them to take such positions as will provide true vertical positionment of the plate-supported metal tube 22 and superjacently supported rod 24 carried by a vibrator (not shown). The tube and red are concentric with one another and free for relative axial movement.

The high voltage power for operating the precipitator may be supplied by input power cables connected with suitable terminals (not shown) associated with the leveling plates. Thus, the plates transmit the high negative voltage input to tube 22 which in turn transmits the voltage to the subjacent framework 26 which supports the depending ionizer wires 42.

Framework 26 comprises an upper frame mechanism 28 connected to tube 22 and a lower frame mechanism 31) connected to tube 24. Frame mechanism 28 comprises a series of longitudinal bars 29 and two transverse bars 34. Frame mechanism 30 comprises a large number of parallel longitudinal bars 36 of angle iron shape connected at their ends by transverse bars 38. A third transverse bar 39 connects mechanism 30 with rod 24.

Bars 36 form the members from which the individual ionizer wires 42 are suspended; therefore these bars are spaced apart in accordance with the spacing between the interposed collector plates 52. The number of bars 36 will of course correspond approximately with the number of collector plates.

Periodically dust may unintentionally accumulate on the ionizer wires. To shake off this dust the wires may be vibrated in vertical directions. The vibrating mechanism may conventionally include a vibrator motor (not shown) arranged above rod 24 to impart vibrating movements thereto. As rod 24 vibrates it causes bars 36 to bow slightly about their connection points with transverse bars 34, thus transmitting a vibrational motion to the ionizer wires. During normal service the entire frame mechanism 39 is a rigid immovable structure.

As shown in FIG. 1, ionizer wires 42 are maintained in taut conditions by individual weights 44 attached to the wire lower ends. Each wire is prevented from any appreciable pendulum motion by an eyebolt 46 or similar guide element suitably aflixed to a longitudinal bar 48; if desired the individual guides can be formed as circular openings in bars 48. The openings in the eyelets or similar guide structure are somewhat oversize with respect to the weights to permit each weightto hang freely in spite of manufacturing tolerance buildups. There is therefore some pendulum movement of each weight. The several bars, 4-8 are connected at their ends by transverse bars 5d. Transverse bars 50 and 38 may be interconnected near their ends by vertical tie rods or tubes 51. It will be understood that the number and spacing of bars 48 will correspond with the number and spacing of the aforementioned bars 36.

Reference will now be made to the general construction of collector plates 52. FIG. 1 shows two sets of rectangular collector plates 52 supported within housing 10* by three transverse I-beams 56, 58 and 60. Each collector plate has a channel-forming strip of metal running along its upper edge. Rods 64 run through the defined channels with their projecting ends supported in separate saddles 66 and 67. Saddles 66 are carried on the undersides of elongated transverse bars 68; saddles 67 are carried on the upper sides of beam 58. Suitable compression springs 69 cushionably support saddles 66 for limited vibrational movements toward and away from beams 56 and 60. Vibrator motors or solenoids 70 having operating shafts 72 may be operatively connected to bars 68 to thus periodically vibrate or rap the collector plates 52, thereby causing accumulated dust to be dislodged into a subjacent collection hopper 53.

The invention As thus far described the arrangement may be considered conventional. The present invention is concerned especially with the mechanisms for connecting wires 42 with frame members 36 and weights 44. As shown in FIG. 2, the upper end portion of an illustrative wire 42 extends within a tubular element 76. Element 76 is slipped onto the Wire while the wire and tubular element are still straight. The tubular element and contained wire section are then bent into the illustrated loop configuration 79. The tubular element is subsequently deformed or crimped at 78, and the protruding end of the wire is bent angularly at 80 to assure retention of the tubular element on the wire.

Support for each wire 42 is provided by a J-bolt 82, which threads into a nut 84 carried on the upper face of bar 36. The nut and bolt may be factory welded together to assure a permanent connection. It will be seen that the hook portion 86 of the J-bolt constitutes a bearing surface for engagement with the loop portion 79 of the tubular connector element.

Wire 42 is directly in line with the straight section 88 of J-bolt 82, thus assuring proper spacing between adjacent wires and collector plates irrespective of different random directions taken by the several hook portions 86. This feature is of some importance when it is realized how many ionizer wires may be employed in a given precipitator.

Customarily the precipitator is shipped from the factory in sections and assembled at the job site. Using the hooktype suspension principle the inidvidual wires 42 (with tubular elements 76 afiixed thereto) can be shipped separately from framework (including bolts 82). Final assembly can be accomplished on the job by merely slipping the loop portions 79 over hook portions 86. Bolts 82 can if desired have random orientations with regard to the planes taken by hook portions 86.

As shown in FIG. 4, the lower end of each wire 42 may be secured within a tubular element 76 identical with element 76 for the wires upper end. The carrier for each weight 44 may take the form of a J-bolt 82a having a hook portion 86a configured similarly to the hook portion on the upper J-bolt. The arrangement is such that the center of gravity of the weight acts along the axis defined by wire 42, thus stabilizing the wire in a truly vertical position without undue stress tending to cause wire breakage. Preferably both the upper and lower tubular elements 76 are affixed to opposite ends of each wire at the factory. At the job site the individual wires are quickly joined to the weights 44 and framework 30, using the J-bolts 82 and 82a.

It will be seen from FIG. 1 that the upper edges of collector plates 52 are located above the lower ends of the adjacent tubular elements 76. Further, the lower edges of the collector plates are located below the upper ends of the lower tubular elements 76. This arrangement confines the ionizing action of wires 42 to the spaces between the upper and lower edges of plates 52. As is now well known, an ionizer wire having a relatively small diameter on the order of .09 inch will when subjected to a high voltage such as kv. emit a corona discharge or glow sufficient to ionize dust particles in the surrounding air stream. If the wire be encased in a tubular element having an outer diameter on the order of .3 inch the encased wire will no longer efiectively ionize the surrounding stream. In the illustrated arrangement the portions of wires 42 beyond or outside the upper and lower edges of plates 52 are encased within large diameter tubular portions which prevent corona discharge. Thus elements 76 function not only as connectors but also as corona shields.

FIG. 5 shows a modified mechanism for supporting a discharge wire. In the FIG. 5 arrangement each bar 36 is provided with a series of slots 37 in its vertical wall, said slots extending upwardly from the bars lower edge and then laterally to form an upwardly facing seat for receiving the bight portion of the loop 79. It will be understood that the FIG. 5 arrangement uses the same connector element 76 that is employed in FIG. 2, the only difference being that the support surface for each connector element is formed directly in bar 36 instead of by the separate bolt 82.

FIG. 6 illustrates a modified mechanism for suspending each wire weight. As there shown, the weight comprises a cylindrical element-0r mass 44a having a platelike hook 86b Welded to its upper end. The center of the hook interior edge is preferably located along the vertical centerline of cylinder 44 to allow the weight to hang truly vertical within a guide (not shown) when hook 86b engages the bight portion of element 76 as shown in FIG. 6.

It will be understood that the above description has necessarily dealt with concrete embodiments of the invention for best disclosure of the invention, but that the invention can be practiced in other than the illustrated forms. For example, the invention can be employed in tube type collectors in addition to the illustrated plate type. Other variations in general arrangement and construction can be employed while still protecting the invention.

It is claimed:

1. An electrostatic precipitator comprising spaced apart vertically extending ionizer wires and spaced apart vertically extending collector elements located to collect particles ionized by said wires; said collector elements having their upper edges located below the upper ends of the wires, and their lower edges located above the lower ends of the wires; an overhead support mechanism for the ionizer Wires substantially above the upper ends thereof; and means connected to the lower end of each wire and tensioning each of said wires for maintaining each wire taut; means connecting the upper end of each of said wires to said support mechanism comprising a tubular corona shield element telescoped onto the upper end portion of each of said wires, each tubular shield element and the contained section of the Wire having portions thereof within and portions thereof, bent out of the axis defined by the respective taut wire and said bent portion defining an engagement surface resting on the support mechanism.

2. The precipitator of claim 1 wherein the bent portions of each tubular element and wire are formed into a loop, the aforementioned engagement surface being defined by the bight portion of the loop.

3. The precipitator of claim 2 wherein the extreme upper end of each wire is extended out of the tubular element and then angularly to help retain the tubular element and Wire together.

4. The precipitator of claim 2 wherein each tubular element is crimped inwardly to clamp the wire with a pinching action.

5. The precipitator of claim 2 wherein the support mechanism includes a horizontal frame and a series of hooks depending therefrom; the bight portions of the hooks constituting bearing surfaces supportably engaged with the bight portions of the loops.

6. The precipitator of claim 3 wherein each hook includes a straight section extending downwardly from the frame, each tubular element including a straight section located below the loop; said hook and loop being configured so that the straight sections are aligned with one another and the axis defined by the taut wire.

7. The precipitator of claim 2 wherein the support mechanism includes a horizontal bar containing a vertical wall; said wall having an exposed lower edge, and a series of slots extending upwardly from said lower edge and then laterally to form an upwardly facing bearing surface supportably engaged with the bight portion of the associated loop.

8. The precipitator of claim 1 wherein the tubular corona shield elements have their lower ends located below the upper edges of the collector elements.

9. The precipitator of claim 1 wherein the means for maintaining each wire taut comprises a weight for the lower end of each wire; means connecting the lower end of each of said wires to the respective weight comprising a second tubular corona shield element telescoped onto the lower end portion of each of said wires; said second tubular element and the contained section of the wire having portions thereof bent out of the axis defined by the taut wire to define a support surface for the weight.

10. The precipitator of claim 9 wherein each weight is provided with an upwardly extending hook, said second tubular elements each having their bent portions formed into loops; the bight portions of the loops constituting support surfaces engaged with the bight portions of the respective upwardly extending hooks.

References Cited UNITED STATES PATENTS 1,252,183 1/1918 Schmidt ct a1. -147 1,323,136 12/1919 Bradley-- 55147 X 2,506,996 5/1950 Crowdei' 55147 X 2,881,857 4/1959 Cosby et al 55l47 2,959,246 11/1960 Phyl et al. 55--147 2,964,125 12/1960 Sylvan 55147 X 2,999,561 9/1961 Phyl 55147 FOREIGN PATENTS 980,435 12/1950 France.

370,148 2/ 1923 Germany.

428,471 5/1935 Great Britain.

OTHER REFERENCES German printed application 'No. 1,05 8,023, printed May 1959.

HARRY B. THORNTON, Primary Examiner.

D. TALBERT, Assistant Examiner. 

1. AN ELECTROSTATIC PRECIPITATOR COMPRISING SPACED APART VERTICALLY EXTENDING IONIZER WIRES AND SPACED APART VERTICALLY EXTENDING COLLECTOR ELEMENTS LOCATED TO COLLECT PARTICLES IONIZED BY SAID WIRES; SAID COLLECTOR ELEMENTS HAVING THEIR UPPER EDGES LOCATED BELOW THE UPPER ENDS OF THE WIRES, AND THEIR LOWER EDGES LOCATED ABOVE THE LOWER ENDS OF THE WIRES; AN OVERHEAD SUPPORT MECHANISM FOR THE IONIZER WIRES SUBSTANTIALLY ABOVE THE UPPER ENDS THEREOF; AND MEANS CONNECTED TO THE LOWER END OF EACH WIRE AND TENSIONING EACH OF SAID WIRES FOR MAINTAINING EACH WIRE TAUT; MEANS CONNECTING THE UPPER END OF EACH OF SAID WIRES TO SAID SUPPORT MECHANISM COMPRISING A TUBULAR CORONA SHIELD ELEMENT TELESCOPED ONTO THE UPPER END PORTION OF EACH OF SAID WIRES, EACH TUBULAR SHIELD ELEMENT AND THE CONTAINED SECTION OF THE WIRE HAVING PORTIONS THEREOF WITHIN AND PORTIONS THEREOF, BENT OUT OF THE AXIS DEFINED BY THE RESPECTIVE TAUT WIRE AND SAID BENT PORTION DEFINING AN ENGAGEMENT SURFACE RESTING ON THE SUPPORT MECHANIMS. 